Impact of intraoperative MRI-guided transsphenoidal surgery on endocrine function and hormone substitution therapy in patients with pituitary adenoma

BACKGROUND: Pituitary adenomas are rare with an incidence of 0.4-8.2 per 105 inhabitants. Symptoms range from headaches to pituitary insufficiency or excessive output of hormones with associated disease. Except for prolactinomas, surgery is recommended as the first line and most effective treatment for the majority of these tumours. One of the refinements of surgical therapy introduced was intraoperative magnetic resonance imaging (iMRI). OBJECTIVE: The aim of this study was to analyse the postoperative pituitary function and the general outcome of patients treated for non-functioning and GH-producing pituitary adenomas with a transsphenoidal iMRI-assisted approach using the PoleStar™ N20 imager. METHODS: A total of 148 consecutive iMRI-guided surgeries for GH-producing and non-functioning pituitary adenomas were retrospectively analysed. Patients' clinical data, endocrinological parameters, clinical examinations and pre-/post- and intraoperative imaging studies were evaluated. RESULTS: A total of 101 patients could be classified as being in remission at follow-up; 26 (17.6%) of them due to iMRI allowing additional tumour removal. A total of 44 patients (29.7%) had more complete tumour removal because remnants were detected by iMRI. The mean hormone levels of patients did not differ significantly between pre- and postoperative examinations. There were 62 patients with preoperative, and 43 patients with postoperative pituitary insufficiency, thus, due to surgery there were 19 (12.8%) patients with improved pituitary function. CONCLUSIONS: The results show this method to be a safe and effective treatment option increasing remission rate and keeping complication rate low. Postoperative pituitary function was preserved or improved - possibly due to more exact iMRI-assisted tumour removal.